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| United States Patent |
5,123,953
|
|
Desbordes
, et al.
|
June 23, 1992
|
Dihalogenated herbicidal sulphones
Abstract
Compounds of formula:
##STR1##
in which: n=0, 1, 2
f=0, 1
Ar is an optionally substituted phenyl or pyridyl group
U a chlorine or bromine atom
V a bromine or chlorine or iodine atom
B is C.sub.1 -C.sub.10 alkyl, C.sub.3 -C.sub.10 cycloalkyl, which are
optionally substituted by 1 to 6 halogen atoms, phenyl or pyridyl or
oxidized pyridyl, which are optionally substituted.
Use of these compounds as herbicides which are selective but especially
antigraminaceous at preemergence.
| Inventors:
|
Desbordes; Philipe (Lyons, FR);
Euvrard; Michel (Fontaines sur Saone, FR);
De Reinach Hirtzbach; Francois (Lyons, FR);
Pearson; Christopher (Hertford, GB3)
|
| Assignee:
|
Rhone-Poulenc Agrochimie (Lyons, FR)
|
| Appl. No.:
|
507664 |
| Filed:
|
April 10, 1990 |
Foreign Application Priority Data
| Current U.S. Class: |
504/250; 504/174; 504/177; 504/178; 504/182; 504/183; 504/244; 504/254; 504/255; 504/256; 504/257; 504/258; 504/260; 504/310; 504/315; 504/326; 504/337; 504/348; 504/349; 504/350; 546/339; 568/27; 568/34; 568/35; 568/56 |
| Intern'l Class: |
A01N 031/08; A01N 043/40 |
| Field of Search: |
71/103,98,94
568/34,35,27,56
|
References Cited
U.S. Patent Documents
| 3634485 | Jan., 1972 | Howe et al. | 260/465.
|
| 4677128 | Jun., 1987 | Place et al. | 514/277.
|
| 4678811 | Jul., 1987 | Franke et al. | 514/721.
|
| Foreign Patent Documents |
| 0326170 | Aug., 1989 | EP.
| |
| 1087879 | Oct., 1967 | GB | 568/34.
|
| 2069492 | Aug., 1981 | GB.
| |
| 2197313 | May., 1988 | GB | 568/34.
|
Other References
Paquette, Leo A., "The Base-Induced Rearrangement of .alpha.-Halo
Sulfones", Accounts of Chemical Research, vol. 1 No. 7, pp. 209-216
(1968).
Schmid, et al., Can. J. Chem., 1974, 52, 1807-1812.
|
Primary Examiner: Brust; Joseph Paul
Assistant Examiner: Haley; Jacqueline
Attorney, Agent or Firm: Scully, Scott, Murphy & Presser
Claims
We claim:
1. A method of inhibiting the growth of a weed which comprises
administering to said weed a herbicidally effective amount of a compound
of the formula:
##STR11##
wherein: n=0, 1, 2
f=0, 1
Ar is chosen from the groups
##STR12##
U is a bromine or chlorine atom, V is a bromine, chlorine or iodine atom,
R.sub.1 is a halogen atom, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy,
C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 haloalkoxy, nitro or cyano
group, C.sub.6 -C.sub.10 aryl, C.sub.7 -C.sub.11 aralkyl, C.sub.6
-C.sub.10 aryloxy optionally substituted by 1 or 2 halogen atoms, or
C.sub.7 -C.sub.11, aralkyloxy optionally substituted by 1 or 2 halogen
atoms, m=0, 1, 2, 3, 4, 5, p=0, 1, 2, 3, 4, the various radicals R.sub.1
being identical or different when m or p is greater than or equal to 2, B
is chosen from C.sub.1 -C.sub.10 alkyl and C.sub.3 -C.sub.10 cycloalkyl
groups, these groups being optionally substituted by 1 to 6 halogen atoms
or chosen from the groups
##STR13##
R.sub.3 having one of the meanings shown for R.sub.1 or NR.sub.4 R.sub.5,
S(O).sub.h R.sub.6, (C=0)R.sub.7,
R.sub.4 and R.sub.5, which are identical or different, are H, C.sub.1
-C.sub.4 alkyl or C.sub.6 -C.sub.10 aryl, R.sub.6 is C.sub.1 -C.sub.4
alkyl,
R.sub.7 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1
-C.sub.4 haloalkoxy or NR.sub.9 R.sub.10,
R.sub.9 and R.sub.10, which are identical or different, are H or C.sub.1
-C.sub.4 alkyl,
the various radicals R.sub.3 being identical or different when
k or g is greater than or equal to 2,
k=0, 1, 2, 3, 4, 5,
g=0, 1, 2, 3, 4,
h=1, 2, and
n'=0, 1, wherein aryl is an aromatic compound containing 6-10 atoms.
2. The method of claim 1 wherein n=2.
3. The method of claim 1 wherein U and V correspond to the bromine atom.
4. The method of claim 1 wherein m is smaller than or equal to 3.
5. The method of claim 1 wherein p is smaller than or equal to 2.
6. The method of claim 1 wherein k is smaller than or equal to 2.
7. The method of claim 1 wherein g is smaller than or equal to 1.
8. The method of claim 1 wherein R.sub.2 is halogen, nitro,
trifluoromethyl, methoxy or methyl.
Description
The invention relates to new compounds, to their use as herbicides
especially in the form of a herbicidal composition, and to a process for
controlling weeds with the aid of these compounds or of these
compositions.
An objective of the present invention is therefore to propose compounds
which can be used as herbicides in pre- or postemergence
Another objective of the present invention is to propose compounds which
can be used as antigraminaceous herbicides in pre- or postemergence.
Another objective of the present invention is to propose compounds which
can be used in pre- or postemergence as selective herbicides for corn and
many dicotyledon crops (especially soya, rape, sunflower, cotton) and
other monocotyledon crops (wheat, rice).
GENERAL DEFINITION OF THE INVENTION
Compounds of formula
##STR2##
in which: n=0, 1, 2
f=0, 1. Ar is chosen from the groups
##STR3##
U being a bromine or chlorine atom, V being a bromine, chlorine or iodine
atom,
R.sub.1 being a halogen atom (especially Cl or Br or F), a C.sub.1 -C.sub.4
alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 haloalkyl, C.sub.1
-C.sub.4 haloalkoxy, nitro or cyano group, C.sub.6 -C.sub.10 aryl
(especially phenyl or naphthyl), C.sub.7 -C.sub.11 aralkyl (especially
benzyl), C.sub.6 -C.sub.10 aryloxy (especially phenoxy or naphlhoxy)
optionally substituted by 1 or 2 halogen atoms or C.sub.7 -C.sub.11
aralkyloxy (especially benzyloxy) optionally substituted by 1 or 2 halogen
atoms,
m=0, 1, 2, 3, 4, 5, p =0, 1, 2, 3, 4, the various radicals R.sub.1 being
identical or different when m or p is greater than or equal to 2,
B is chosen from C.sub.1 -C.sub.10 alkyl and C.sub.3 -C.sub.10 cycloalkyl
groups, these groups being optionally substituted by 1 to 6 halogen atoms
or chosen from the groups
##STR4##
R.sub.3 having one of the meanings shown for R.sub.1 or NR.sub.4 R.sub.5,
S(O).sub.h R.sub.6, (C.dbd.O)R.sub.7,
R.sub.4 and R.sub.5, which are identical or different, are H, C.sub.1
-C.sub.4 alkyl or C.sub.6 -C.sub.10 aryl, R.sub.6 is C.sub.1 -C.sub.4
alkyl,
R.sub.7 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1
-C.sub.4 haloalkoxy or
NR.sub.9 R.sub.10, R.sub.9 and R.sub.10 which are identical or different,
are
H or C.sub.1 -C.sub.4 alkyl,
the varius radicals R.sub.3 being identical or different when
k or g is greater than or equal to 2,
k=0, 1, 2, 3, 4, 5, g=0, 1, 2, 3, 4,
h=0, 1, 2,
n=0, 1.
The aliphatic groups may be linear or branched.
PREFERRED ALTERNATIVE FORMS
Depending on the preferred embodiments, the following alternative forms
will be chosen, taken in combination or otherwise: n=2, U and V=Br, m
smaller than or equal to 3, p smaller than or equal to 2, k smaller than
or equal to 2, g smaller than or equal to 1, R.sub.1 is halogen, nitro,
trifluoromethyl, methoxy or methyl.
The compounds of formula (I) and the compounds which may be employed as
intermediates in the processes of preparation, and which will be defined
when these processes are described, can exist in one or more isomeric
forms, depending on the number of asymmetric centres in the molecule. The
invention consequently relates both to all the optical isomers and to
their racemic mixtures and the corresponding diastereoisomers. The
separation of the diastereoisomers and/or of the optical isomers can be
carried out according to methods which are known per se.
PROCESSES FOR THE PREPARATION OF THE COMPOUND OF FORMULA (I)
The compounds of formula (I) in which n=0, 1, 2, the other substituents
having the same definition as that shown in the general definition of the
invention, may be prepared by bringing a compound of formula:
##STR5##
in which Ar, n, f and B have the same meaning as in the general definition
of the invention, into contact with halides UV like chlorine (U=Cl, V=Cl),
bromine (U=Br, V=Br), chlorine iodide (U=Cl, V=I), bromine iodide (U=Br,
V=I) or chlorine bromide (U=Cl, V=Br), in an aprotic inert solvent such as
chloroform, carbon tetrachloride, tetrahydrofuran, dimethoxyethane or
acetonitrile, in the presence or otherwise of an acid such as acetic acid
or hydrochloric acid at a temperature of -78.degree. C. to 60.degree. C.
(preferably 0.degree. C. to 20.degree. C.) and in a molar ratio IA:UV of
between 1 and 5 (preferably 1 and 2). This reaction is known especially
from J. March, "Advanced Organic Chemistry", publ. McGraw-Hill (1985), p.
724-726, S. Akiyoshi and K. Okuno, J. Amer. Chem Soc. (1952), 74, 5759 and
F. G. Weber, Tetrahedron (1969), 25, 4283.
These same compounds of formula (I) in which n=0, 1 or 2, the other
substituents having the same definition as that shown in the general
definition of the invention, can also be prepared by the action on a
compound of formula (IA) where the substituents have the same meaning as
in the general definition of the invention, of a halogenating agent ZV, V
being the chlorine or bromine atom and Z an acetamido radical, such as
N-haloacetamide or N-halosuccinimide in the presence of a donor of a
halide anion U, U being the chlorine or bromine atom, such as the hydrogen
halide acids HU, ammonium halides (R).sub.4 NU, R being an alkyl radical,
or the salts MU, M being an atom of an alkali or alkaline-earth metal or a
silver atom in an inert solvent such as methylene chloride, chloroform,
acetonitrile, dimethoxyethane or acetic acid at a temperature of
-78.degree. C. to 60.degree. C. (preferably 0.degree. C. to 20.degree. C.)
and in a molar ratio IA:ZV:U of between 1:1:1 and 1:5:100 (preferably
1:2:5).
This reaction is known especially from J. March, ibid. p. 725, R. E.
Buckles and J. W. Long, J. Amer. Chem. Soc (1959), 81, 2191, A. Marquet
and J. Jacques, Tetrahedron Letters (1959), 9, 24 and C. H. Robinson et
al., J. Amer. Chem. Soc. (1959), 81, 2191.
The compounds of formula (I) in which n=0 or 1, the other substituents
having the same definition as that shown in the general definition of the
invention, can be oxidized to a sulphoxide (n=1) by one equivalent of
oxidizing agent at a temperature of -70.degree. C. to 5.degree. C.
(generally 0.degree. C.) or can be oxidized to a sulphone (n=2) by two or
more equivalents of oxidizing agent at a tempera ture of 0.degree. C. to
60.degree. C. (generally 10.degree. C. to 30.degree. C.) by many oxidizing
agents, such as KMnO.sub.4, H.sub.2 O.sub.2, CH.sub.3 CO.sub.3 H,
perbenzoic acids, KHSO.sub.5, and others, by following very many known
methods, J. March, ibid. p. 1089-1090 and B. M. Trost and R. Braslau, J.
Org. Chem. (1988), 53, 532.
PROCESS FOR THE PREPARATION OF THE COMPOUND OF FORMULA IA
Method A
The compounds of formula (IA) in which n=2, the other substituents having
the same definition as that shown in the general definition of the
invention, can be obtained by bringing a compound of formula
##STR6##
in which Ar, R.sub.1 and m or p have the same meaning as in the general
definition of the invention, and T is a chlorine or bromine atom, into
contact with a compound of formula:
MSO.sub.2 (CH.sub.2).sub.f -B (III)
f and B having the same definition as that shown in the definition of the
invention,
M being an atom of an alkali or alkaline-earth metal (expecially Li, K,
Na).
The reaction is generally performed in a dipolar aprotic solvent,
especially dimethylformamide or N-methylpyrrolidone, or in water in a
mixture in the proportions of 5/95 to 90/10 (preferably 10/90 to 50/50)
with a water-soluble solvent such as alcohols, acetone, acetonitrile or
dimethoxy-ethane, in the presence or otherwise of a catalytic or other
quantity of alkali metal iodide, in the presence or absence of a catalytic
quantity of a phase transfer agent such as tetrabutylammonium halides, at
a temperature of between 25.degree. C. and 150.degree. C. (preferably
60.degree. C. to 120.degree. C.) and in a molar ratio II:III of between 1
and 10 (preferably 1 and 2).
This reaction is known especially from J. March, ibid. p. 363. The
compounds of formula (II) where T is chlorine and Ar is 1-Ar (phenyl
nucleus) are prepared by chlorination of a 2-phenyl-1-propene compound of
formula:
##STR7##
in which Ar is 1-Ar (phenyl nucleus), R.sub.1 and m having the same
meaning as in the definition of the general fcrmula, by means of the
reactant Ca(OCl).sub.2 /CO.sub.2. This reaction is described by S. G.
Hegde and J. Wolinsky, Tetrahedron Letters (1981), 22, 5019.
These same compounds of formula (II) where T is chlorine and Ar is 1-Ar
(phenyl nucleus) can be prepared by chlorination of the compounds of
formula (IV) by means of the SO.sub.2 Cl.sub.2 /Na.sub.2 CO.sub.3 reactant
according to M. Bulliard et al., Tetrahedron Letters (1989), 30, 5767.
The compounds of formula (II) where T is chlorine, Ar having the same
definition as that shown in the general definition of the invention, can
also be prepared by chlorination of the abovementioned compounds of
formula (IV) using N-chlorosuccinimide in the presence of bisaryl
diselenide according to the process of K. B. Sharpless and T. Hori, J.
Org. Chem. (1979), 44, 4204.
The compounds of formula (II) where T is chlorine or bromine, Ar having the
same definition as that shown in the general definition of the invention,
can also be prepared by thermal or photochemical radical halogenation of
the compound of formula (IV) using N-halosuccinimide in an aprotic solvent
such as carbon tetrachloride or in the absence of solvent, with or without
a free-radical initiator, at a temperature of 20.degree. C. to 170.degree.
C. (preferably 80.degree. C. to 100.degree. C.), according to S. F. Reed,
J. Org. Chem. (1965), 30, 3258. They can also be prepared by halogenation
of the compounds of formula (II) where T is OH, Ar having the same
definition as that shown in the general definition of the invention, with
a halogenating agent such as SOCl.sub.2, POCl.sub.3, PBr.sub.3, J. March,
ibid. p. 382-384, or with the LiCl/CH.sub.3 SO.sub.2 Cl/collidine reactant
according to E. W. Collington and A. I. Meyers, J. Org. Chem. (1971), 36,
3044.
The compounds of formula (II) where T is OH, Ar having the same definition
as that shown in the general definition of the invention, can be prepared
by allylic oxidation of the compound of formula (IV) using selenium oxide,
catalytic or otherwise, in the presence of an oxidizing agent such as
tert-butyl hydroperoxide, in an inert solvent such as halogenated solvents
(preferably methylene chloride) or tert-butanol, in the presence of
inorganic or organic acid, according to M. A. Umbreit and K. B. Sharpless,
J. Amer. Chem. Soc. (1977), 99, 5526.
The compounds of formula (IV) can be obtained by dehydration of a
2-aryl-2-propanol compound of formula:
##STR8##
in which Ar, R.sub.1 and m or p have the same meaning as in the general
definition of the invention, using dehydrating agents such as P.sub.2
O.sub.5, KHSO.sub.4, POCl.sub.3 /pyridine and others, according to J.
March, ibid. p. 901-903.
The compounds of formula (V) can be prepared by bringing acetophenone or
acetylpyridine or an acid derivative of formula:
##STR9##
in which Ar, R.sub.1 and m or p have the same meaning as in the general
definition of the invention and W is methyl, alkoxy (corresponding benzoic
ester) or chlorine, into contact with one or two equivalents of
methylmagnesium halide according to J. March, ibid. p. 816-822.
The compounds of formula (VI) are obtained in a manner which is known per
se. The compounds of formula (III) can be prepared by reduction of the
corresponding sulphonyl halides (generally a chloride) with zinc, with
sodium or potassium iodide and with sodium sulphite, accordinq to J.
March, ibid. p. 445-446 and W. E. Truce and A. H. Murphy, Chem Rev.
(1951), 48, 69. The sulphonyl halides can be prepared according to J.
March, ibid. p. 1172.
The compounds of formula (III) can also be prepared by reaction of an
organometallic (usually lithium) compound of formula:
M(CH.sub.2).sub.f -B (IIIA)
f and B having the same meaning as that shown in the definition of the
invention, M being especially lithium, with sulphur dioxide SO.sub.2, at a
temperature of between -78.degree. C. and 20.degree. C. (preferably
-78.degree. C. to -40.degree. C.) in the absence or in the presence of an
aprotic solvent such as ethyl ether or tetrahydrofuran, according to H. W.
Pinnick and M. A. Reynolds, J. Org. Chem. (1979), 44, 160 and J. March,
ibid. p. 550.
The compounds of formula (IIIA) are obtained in a manner which is known per
se.
Method B
The compounds of formula (IA) in which n=0, 1 or 2 can be prepared by
reaction of the alkali metal salt of an aryl or alkyl thiolate of formula:
M'S(CH.sub.2).sub.f -B (VII)
in which M' is an alkali metal or alkaline-earth metal atom, especially
sodium or potassium, f and B having the same definition as that shown in
the definition of the invention, with a compound of formula (II) where T
is halogen, described above, in a protic or aprotic inert solvent such as
ketones, alcohols, tetrahydrofuran, acetonitrile or aprotic dipolar
solvents such as dimethylformamide, at a temperature of 0.degree. C. to
80.degree. C., (generally 25.degree. C. to 60.degree. C.) in a molar ratio
II:VII which is generally between 1 and 10 (preferably 1 and 2).
The sulphide thus obtained (n=0) can be oxidized to sulphoxide (n=1) using
one equivalent of oxidizing agent at a temperature of -70.degree. C. to
5.degree. C. (generally 0.degree. C.) or can be oxidized to sulphone (n=2)
using two or more equivalents of oxidizing agent at a temperature of
0.degree. C. to 60.degree. C. (generally 10.degree. C. to 30.degree. C.)
using numerous oxidizing agents such as KMnO.sub.4, H.sub.2 O.sub.2,
CH.sub.3 CO.sub.3 H, perbenzoic acids, KHSO.sub.5, and others, using very
numerous known methods: J. March, ibid. p. 1089-1090 and B. M. Trost and
R. Braslau, J. Org. Chem (1988), 53, 532.
Another subject of the invention is the new products (II) to (VII) which
can be used for making use of the process just described.
The following examples illustrate the invention.
EXAMPLE 1
2-Phenyl-1-phenylsulphonyl-2-propene (10.3 g, 0.04 moles) is dissolved in
chloroform (100 cc). Bromine (6.8 g, 0.042 moles) is then added dropwise
until the colour persists. The organic phase is washed with a 5% solution
of sodium thiosulphate (50 cc), water (50 cc) and is dried over
MgSO.sub.4. After evaporation, a colourless oil (18.8 g) is obtained. This
oil is dissolved in a mixture of chloroform (20 cc) and ether (40 cc) and
is stored overnight at -18.degree. C. White crystals of
1,2-dibromo-2-phenyl-3-phenylsulphonylpropane (14.3 g, 86%) are filtered
off. Mp=74.degree. C.
EXAMPLE 2
2-Phenyl-1-phenylsulphonyl-2-propene (2.6 g, 0.01 mole) is dissolved in
chloroform (20 cc). The solution is cooled to 5.degree. C. and chlorine
iodide (1.8 g, 0.011 moles) in solution in chloroform (5 cc) is added
dropwise. The mixture is stirred at 5.degree. C. for two hours and is then
treated in the same way as in Example 1. Evaporation leaves a yellow oil
(5.3 g). This oil is dissolved in ether (7.5 cc) and is stored overnight
at -18.degree. C. Off-white crystals of
2-chloro-1-iodo-2-phenyl-3-phenylsulphonylpropane (3.3 g, 78%) are
filtered off. Mp=75.5.degree. C. (dec.).
EXAMPLE 3
2-Phenyl-1-phenylsulphonyl-2-propene (2.6 g, 0.01 mole) is suspended in a
mixture of acetic acid (50 cc) and 35% hydrochloric acid (10 cc). Chlorine
is then introduced into the reaction mixture until the allyl sulphone has
completely dissolved (5 min). The mixture is poured into ice and water
(250 g) and is stirred vigorously until a resin forms.
The resin is filtered off and dissolved in methylene chloride (100 cc) and
the organic phase is washed with a 10% sodium carbonate solution (100 cc),
water (2.times.100 cc) and is dried over MgSO.sub.4. Evaporation leaves a
yellow oil (4.8 g). This oil is dissolved in ether (20 cc) and is stored
overnight at -18.degree. C. After filtration and recrystallization from
ethanol, pale yellow crystals of
1,2-dichloro-2-phenyl-3-phenylsulphonylpropane (1.2 g, 36%) are obtained.
Mp=95.degree. C.
EXAMPLE 4
2-Phenyl-1-phenylsulphonyl-2-propene (2.6 g, 0.01 mole) is suspended in
acetic acid (50 cc). Lithium chloride (2 g, 0.05 moles) and 35%
hydrochloric acid (5 cc) are then added and, finally, N-bromosuccinimide
(1.8 g, 0.01 mole). The mixture is stirred until dissolved (15 min) and is
then treated in the same way as in Example 3. Evaporation leaves a yellow
oil (3.6 g) which is redissolved in ether (10 cc) and stored overnight at
-18.degree. C. White crystals of
1-bromo-2-chloro-2-phenyl-3-phenylsulphonylpropane (1.5 g, 40%) are
filtered off. Mp=91.degree. C.
EXAMPLE 5
Using the same method as in Example 1,
2-(6-chloro-2-pyridyl)-1-phenylsulphonyl-2-propene (1.0 g, 0.0035 moles)
is treated with bromine (0.6 g, 0.0038 moles) in chloroform. After
treatment, evaporation leaves an oil (1.6 g) which is crystallized from
ether (40 cc) overnight at -18.degree. C. White crystals of
1,2-dibromo-2-(6-chloro-2-pyridyl)-3-phenylsulphonylpropane (1.2 g, 75%)
are filtered off. Mp=119.degree. C.
EXAMPLE 6
Using the same method as in Example 1,
2-(6-chloro-2-pyridyl)-1-cyclopropylsulphonyl-2-propene (1.4 g, 0.0054
moles) is treated with bromine (0.87 g, 0.0054 moles) in chloroform. After
treatment, evaporation leaves an oil (2.1 g), which is chromatographed on
silica (eluent: 80/20 heptane/chloroform) to give crystals of
1,2-dibromo-2-(6-chloro-2-pyridyl)-3-cyclopropylsulphonylpropane (0.7 g,
31%). Mp=75.degree. C. The compounds brought together in the table below
were prepared according to the method of Example 1.
______________________________________
##STR10##
Mp (solvent)
Example
R1 f B n.sub.D (temperature)
______________________________________
7 2-F 0 phenyl 123.degree. C.
(CHCl.sub.3 /pentane)
8 4-Me 0 phenyl 101.degree. C.
(CHCl.sub.3 /Et.sub.2 O)
9 4-F 0 phenyl 103.degree. C.
(CHCl.sub.3 /Et.sub.2 O)
10 3,5-diCl 0 phenyl 135.degree. C.
(CHCl.sub.3 /Et.sub.2 O)
11 H 1 phenyl 93.degree. C.
(CHCl.sub.3 /Et.sub.2 O)
12 H 0 4-F phenyl 103.degree. C.
(CHCl.sub.3 /pentane)
13 H 0 2-Cl phenyl
120.degree. C.
(CHCl.sub.3 /pentane)
14 H 0 2-F phenyl 82.degree. C. (Et.sub.2 O)
15 H 0 2-Me phenyl
74.degree. C.
(CHCl.sub.3 /Et.sub.2 O)
16 H 0 3-Me phenyl
95.degree. C.
(CHCl.sub.3 /Et.sub.2 O)
17 H 0 2-Cl 4-F phenyl
110.degree. C.
(Et.sub.2 O/pentane)
18 3-Cl 0 2-Cl phenyl
87.degree. C.
(CH.sub.2 Cl.sub.2 /iPr.sub.2 O)
19 3-F 0 2-Cl phenyl
97.degree. C.
(Et.sub.2 O/pentane)
20 3-CF.sub.3
0 2-Me phenyl
92.degree. C. (Et.sub.2 O)
21 3,5-diCl 0 4-F phenyl 133.5.degree. C.
(CHCl.sub.3 /Et.sub.2 O)
22 3,5-diCl 0 2-Me phenyl
117.degree. C.
(chromatography)
23 H 0 (CH.sub.2).sub.3 CH.sub.3
1.5768 (25.degree. C.)
24 H 0 cyclopropyl
95.degree. C. (Et.sub.2 O)
25 3-Cl 0 CH(CH.sub.3).sub.2
1.5717 (24.degree. C.)
______________________________________
Preparation of 2-phenyl-1-phenylsulphonyl-2-propene
2-Phenyl-1-propene (130 cc, 1 mole) is dissolved in methylene chloride
(1,500 cc). Water (300 cc) and calcium hypochlorite (101.5 g, 0.5 moles)
containing 70% of active chlorine are added. Solid carbon dioxide is added
for 2 hours with very energetic stirring. The two phases are separated and
the organic phase is dried over MgSO.sub.4.
After evaporation, a yellow oil (145 g) is obtained. NMR analysis (60 MHz)
shows the presence of 45% of 1-chloro-2-phenyl-2-propene, 45% of
1-chloro-2-phenyl-1-propene and 10% of 1-chloro-2-phenyl-2-propanol.
This mixture (17 g, 0.05 moles as 1-chloro-2-phenyl-2-propene) is dissolved
in dimethylformamide (100 cc). Sodium benzenesulphinate (8.2 g, 0.05
moles) is added and the mixture is heated to 70.degree. C. for 2 h. The
reaction mixture is poured into ice and water (350 g). It is stirred
vigorously with pentane (150 cc) to extract the unreacted
1-chloro-2-phenyl-1-propene and 1-chloro-2-phenyl-2-propanol for 15 to 30
min until crystallization is complete. The crystals formed are filtered
off, are washed with pentane (50 cc) and diisopropyl ether (50 cc), are
drained thoroughly and are dried. 2-Phenyl-1-phenylsulphonyl-2-propene
(9.8 g, 76%) is obtained. Mp=105.degree. C.
The following compounds were prepared in the same way:
2-(2-fluorophenyl)-1-phenylsulphonyl-2-propene, mp=95.degree. C.,
2-(4-methylphenyl)-1-phenylsulphonyl-2-propene, mp=92.degree. C.,
2-(4-fluorophenyl)-1-phenylsulphonyl-2-propene, mp=85.degree. C.,
2-(3-chlorophenyl)-1-(2-chlorophenylsulphonyl)-2-propene, mp=87.degree. C.,
1-(2-chlorophenylsulphonyl)-2-phenyl-2-propene, n.sup.22 =1.6090,
2-(3,5-dichlorophenyl)-1-phenylsulphonyl-2-propene, mp=98.degree. C.,
1-(2-chlorophenylsulphonyl)-2-(3-fluorophenyl)-2-propene, n.sub.D.sup.24
=1.5860,
1-(2-fluorophenylsulphonyl)-2-phenyl-2-propene, mp=84.degree. C.,
1-butylsulphonyl-2-phenyl-2-propene, mp=25.degree. C.,
1-cyclopropylsulphonyl-2-phenyl-2-propene, mp=76.degree. C.
Preparation of 1-benzylsulphonyl-2-phenyl-2-propene
Potassium carbonate (27 g, 0.19 moles) is suspended in acetone (600 cc).
The mixture is heated to 60.degree. C. and is degassed with nitrogen. A
mixture of benzyl mercaptan (21.7 g, 0.17 moles) and the allyl chloride
(59 g, 0.17 moles as 1-chloro-2-phenyl-2-propene) prepared according to
the preceding example, in solution in acetone (175 cc) is added dropwise
at 60.degree. C. The mixture is stirred at 60.degree. C. for two hours.
The reaction mixture is poured into ice and water (2,000 g) and is
reextracted with ether (3.times.500 cc). The organic phase is washed with
water until neutral and is dried over MgSO.sub.4. Evaporation leaves a
yellow oil (82.5 g), which is chromatographed on silica (eluent heptane,
then 99/1 heptane/chloroform) to give 1-benzylthio-2-phenyl-2-propene
(19.5 g, 46%). Colourless oil. n.sub.D.sup.25 =1.6041.
1-Benzylthio-2-phenyl-2-propene (13.2 g, 0.055 moles) is dissolved in
methanol (300 cc) and water (300 cc). Oxone (36.9 g, 0.12 moles as
HKSO.sub.5) is added portionwise and the mixture is stirred at ambient
temperature for three hours. The reaction mixture is diluted with water
(1,000 cc), pentane (100 cc) is added, and the mixture is stirred
vigorously until crystallization takes place. White crystals of
1-benzylsulphonyl-2-phenyl-2-propene (10.7 g, 72%) are obtained by
filtration followed by drying. Mp=118.degree. C.
The following compounds were prepared in the same way:
2-(3-chlorophenyl)-1-isopropylsulphonyl-2-propene, n.sub.D.sup.25 =1.5715,
1-(4-fluorophenylsulphonyl)-2-phenyl-2-propene, mp=83.degree. C.,
1-(3-methylphenylsulphonyl)-2-phenyl-2-propene, mp=61.degree. C.
1-(2-methylphenylsulphonyl)-2-phenyl-2-propene, mp=62.degree. C.,
1-(2-chloro-4-fluorophenylsulphonyl)-2-phenyl-2-propene, mp=64.degree. C.,
2-(3,5-dichlorophenyl)-1-(4-fluorophenylsulphonyl)-2-propene,
mp=105.degree. C.,
2-(3,5-dichlorophenyl)-1-(2-methylphenylsulphonyl)-2-propene, mp=72.degree.
C., 1-(2-methylphenylsulphonyl)-2-(3-trifluoromethylphenyl)-2-propene,
mp=51.degree. C.
Preparation of 2-(6-chloro-2-pyridyl)-1-phenyl-sulphonyl-2-propene
2-(6-Chloro-2-pyridyl)-1-propene (15.3 g, 0.1 mole) is dissolved in
1,2-dichloroethane (200 cc). Bis(4-chlorophenyl) diselenide (0.5 g,
catalytic) and N-chlorosuccinimide (14.7 g, 0.11 moles) are added and
heated to 60.degree. C. for 24 hours. The reaction mixture is concentrated
down to one third, the succinimide is filtered off and the organic phase
is washed with water (2.times.200 cc), with a 15% solution of sodium
bicarbonate (1.times.200 cc) and water (2.times.200 cc) and is dried over
MgSO.sub.4. Crude: 13.9 g.
NMR analysis (60 MHz) shows the presence of 55% of
1-chloro-2-(6-chloro-2-pyridyl)-2-propene and 45% of
1-chloro-2-(6-chloro-2-pyridyl)-1-propene.
In a similar manner to the preparation of
2-phenyl-1-phenylsulphonyl-2-propene, this mixture (7 g, 0.02 moles as
1-chloro-2-(6-chloro-2-pyridyl)-2-propene) is treated with sodium
benzenesulphinate to obtain, after treatment,
2-(6-chloro-2-pyridyl)-1-phenylsulphonyl-2-propene (4.3 g, 73%).
Mp=135.degree. C.
The following compound was prepared in the same way:
2-(6-chloro-2-pyridyl)-1-cyclopropylsulphonyl-2-propene, n.sub.D.sup.24
=1.5730.
The invention also relates to the use of the compounds of formula (I) as a
herbicide. As weeds which can be controlled or destroyed using the
compounds of formula (I) there may be mentioned:
______________________________________
Graminaceae/Cyperaceae
Abbreviation
Latin name English name
______________________________________
AVE Avena fatua Wild oat
ECH Echinochloa crusgalli
Panic grass
LOL Lolium multiflorum
Italian ryegrass
CYP Cyperus esculentus
Chufa flat sedge
DIG Digitaria sanguinalis
Hairy fingergrass
ALO Alopercurus myosuroides
Slender foxtail
______________________________________
Most of the time, the compounds of formula (I) are employed in the form of
a herbicidal composition comprising one or more agriculturally acceptable
carriers.
In fact, for their practical use, the compounds according to the invention
are rarely employed by themselves. In most cases these compounds form part
of compositions. These compositions, which can be employed as herbicidal
agents, contain as active substance a compound according to the invention
such as described above mixed with agriculturally acceptable solid or
liquid carriers and surface-active agents which are also agriculturally
acceptable. In particular, the usual inert carriers and the usual
surface-active agents can be employed. These compositions also form part
of the invention.
These compositions may also contain all kinds of other ingredients such as,
for example, protective colloids, adhesives, thickeners, thixotropic
agents, penetrating agents, stabilizers, sequestrants and the like. More
generally, the compounds employed in the invention may be used in
combination with any of the solid or liquid additives corresponding to the
usual formulation techniques.
As a general rule, the compositions according to the invention usually
contain approximately from 0.05 to 95% (by weight) of a compound according
to the invention, one or more solid or liquid carriers and, optionally,
one or more surface-active agents.
In the present description the term "carrier" denotes a natural or
synthetic, organic or inorganic substance with which the compound is
combined to facilitate its application to the plant, to seed or to the
soil. This carrier is therefore generally inert and it must be
agriculturally acceptable, especially on the treated plant. The carrier
may be solid (clays, natural or synthetic silicates, silica, resins,
waxes, solid fertilizers, and the like) or liquid (water, alcohols,
especially butanol, and the like).
The surface-active agent may be an emulsifying, dispersing or wetting agent
of an ionic or nonionic type or a mixture of such surface-active agents.
There may be mentioned, for example, salts of polyacrylic acids, salts of
lignosulphonic acids, salts of phenolsulphonic or naphthalenesulphonic
acids, polycondensates of ethylene oxide with fatty alcohols or with fatty
acids or with fatty amines, substituted phenols (especially alkylphenols
or arylphenols), salts of sulphosuccinic acid esters, taurine derivatives
(especially alkyl taurates), phosphoric esters of polycondensates of
ethylene oxide with alcohols or phenols, esters of fatty acids and of
polyols, and sulphate, sulphonate and phosphate functional derivatives of
the above compounds.
The presence of at least one surface-active agent is generally
indispensible when the compound and/or the inert carrier are not
water-soluble and the vector agent of the application is water.
Thus, therefore, the compositions for agricultural use according to the
invention may contain the active substances according to the invention
within very wide limits, ranging from 5.times.10.sup.-5 % to 95% (by
weight). Their content of surface-active agent is advantageously between
5% and 40% by weight.
These compositions according to the invention are themselves in fairly
diverse solid or liquid forms.
As solid forms of compositions, there may be mentioned dusting powders
(with a compound content which can go up to 100%) and granulates,
especially those obtained by extrusion, by compacting, by impregnation of
a granulated carrier or by granulation starting with a powder (the content
of compound in these granulates being between 0.5 and 80% in these latter
cases).
The wettable powders (or spraying powder) are usually prepared so that they
contain 20 to 95% of active substance, and they usually contain, in
addition to the solid carrier, from 0 to 30% of a wetting agent, from 3 to
20% of a dispersing agent and, when necessary, from 0 to 10% of one or
more stabilizers and/or other additives, such as penetrating agents,
adhesives or anticaking agents, colorants, and the like.
To obtain the spraying powders or wettable powders, the active substances
are mixed intimately with the additional substances in suitable mixers and
are ground up using mills or other suitable grinders. This yields spraying
powders whose wettability and suspendability are advantageous; they can be
made into a suspension with water at any desired concentration, and these
suspensions can be employed very advantageously, in particular for
application to plant foliage.
Pastes can be produced instead of the wettable powders. The conditions and
methods of production and of use cf these pastes are similar to those of
the wettable powders or spraying powders.
By way of example, here are various compositions of wettable powders (or
spraying powders):
EXAMPLE F 1
______________________________________
active substance (compound No. 1)
50%
fatty alcohol/ethylene oxide condensate
2.5%
(wetting agent)
phenylethylphenol/ethylene oxide condensate
5%
(dispersing agent)
chalk (inert carrier) 42.5%
______________________________________
EXAMPLE F 2
______________________________________
active substance (compound No. 1)
10%
syntheic oxo C.sub.13 alcohol of branched
0.75%
type, condensed with 8 to 10 ethylene
oxides (wetting agent)
neutral calcium lignosulphonate
12%
(dispersing agent)
calcium carbonate (inert filler)
q.s. 100%
______________________________________
EXAMPLE F 3
This wettable powder contains the same ingredients as in the preceding
example, in the following proportions:
______________________________________
active substance 75%
wetting agent 1.50%
dispersing agent 8%
calcium carbonate (inert filler)
q.s. 100%
______________________________________
EXAMPLE F 4
______________________________________
active substance (compound No. 1)
90%
fatty alcohol/ethylene oxide condensate
4%
(wetting agent)
phenylethylphenol/ethylene oxide condensate
6%
(dispersing agent)
______________________________________
EXAMPLE F 5
______________________________________
active substance (compound No. 1)
50%
mixture of anionic and nonionic
2.5%
surfactants (wetting agent)
sodium lignosulphonate (dispersing agent)
5%
kaolin clay (inert carrier)
42.5%
______________________________________
The compounds according to the invention can be formulated in the form of
water-dispersible granulates which are also included within the scope of
the invention.
These dispersible granulates, with an apparent density which is generally
between approximately 0.3 and 0.6, have a particle size which is generally
between approximately 150 and 2,000 and preferably between 300 and 1,500
microns.
The content of active substance in these granulates is generally between
approximately 1% and 90%, and preferably between 25% and 90%.
The remainder of the granulate is essentially made up of a solid filler and
optionally of surface-active adjuvants endowing the granulate with
properties of dispersibility in water. These granulates can be essentially
of two distinct types, depending on whether the filler contained is or is
not water-soluble. When the filler is water-soluble, it may be inorganic
or, preferably, organic. Excellent results have been obtained with urea.
In the case of an insouble filler, the latter is preferably inorganic,
such as, for example, kaolin or bentonite. It is then advantageously
accompanied by surface-active agents (in a proportion of 2 to 20% by
weight of the granulate) more than half of which consists, for example, of
at least one essentially anionic dispersing agent such as an alkali metal
or alkaline-earth metal polynaphthalenesulphonate or an alkali metal or
alkaline-earth metal lignosulphonate, the remainder consisting of nonionic
or anionic wetting agents, such as an alkali metal or alkaline-earth metal
alkylnaphthalenesulphonate.
Furthermore other adjuvants, such as antifoaming agents, may be added,
although this is not essential.
The granulate according to the invention may be prepared by mixing the
necessary ingredients, followed by granulation according to a number of
techniques which are known per se (pelletizer, fluid bed, sprayer,
extrusion, and the like). The finishing step is generally crushing
followed by screening to the chosen particle size within the limits noted
above.
It is preferably obtained by extrusion, the operation being carried out as
indicated in the examples below.
EXAMPLE F 6
Dispersible Granulates
90% by weight of active substance (compound No. 1) and 10% of urea pearls
are mixed in a blender. The mixture is then ground in a pin mill. A powder
is obtained, which is moistened with approximately 8% by weight of water.
The moist powder is extruded in an extruder with a perforated roller. A
granulate is obtained, which is dried and then crushed and screened, so as
to retain only granules of a size between 150 and 2,000 microns
respectively.
EXAMPLE F 7
Dispersible Granulates
The following constituents are mixed in a blender:
______________________________________
active substance (compound No. 1)
75%
wetting agent (sodium alkylnaphthalene-
2%
sulphonate)
dispersing agent (sodium polynaphthalene-
8%
sulphonate)
water-insoluble inert filler (kaolin)
15%
______________________________________
This mixture is granulated in a fluid bed, in the presence of water, and is
then dried, crushed and screened so as to obtain granules of size between
0.15 and 0.80 mm.
These granulates can then be employed by themselves, in solution or in
dispersion in water, so as to obtain the required dose. They can also be
employed to prepare combinations with other active substances, especially
fungicides, the latter being in the form of wettable powders or of
granulates or aqueous suspensions.
The compounds of formula (I) can, furthermore, be employed in the form of
dusting powders; it is also possible to employ a composition comprising 50
g of active substance and 950 g of talc; it is also possible to employ a
composition comprising 20 g of active substance, 10 g of finely divided
silica and 970 g of talc; these constituents are mixed and ground and the
mixture is applied by dusting.
As forms of compositions which are liquid or intended to constitute liquid
compositions when applied, there may be mentioned solutions, in particular
water-soluble concentrates, emulsifiable concentrates, emulsions,
concentrated suspensions, aerosols, wettable powders (or spraying powder)
and pastes.
Emulsifiable or soluble concentrates in most cases contain 10 to 80% of
active substance, while emulsions or solutions which are ready for use
contain 0.001 to 20% of active substance.
In addition to the solvent, the emulsifiable concentrates may, when
necessary, contain 2 to 20% of suitable additives such as stabilizers,
surface-active agents, penetrating agents, corrosion inhibitors, colorants
or the adhesives referred to above.
From these concentrates it is possible, by dilution with water, to obtain
emulsions of any desired concentration, which are particularly suitable
for application to crops.
By way of example, here is the composition of some emulsifiable
concentrates:
EXAMPLE F 8
______________________________________
active substance 400 g/l
alkali metal dodecylbenzenesulphonate
24 g/l
nonylphenol condensate with 10 molecules
16 g/l
of ethylene oxide
cyclohexanone 200 g/l
aromatic solvent q.s. 1 liter
______________________________________
According to another emulsifiable concentrate formulation, the following
are employed:
EXAMPLE F 9
______________________________________
active substance 250 g
epoxidized vegetable oil
25 g
mixture of alkylarylsulphonate and of
100 g
polyglycol ether and of fatty alcohols
dimethylformamide 50 g
xylene 575 g
______________________________________
Flowables, which can also be applied by dusting, are prepared so as to
obtain a stable fluid product which does not settle and usually contain
from 10 to 75% of active substance, from 0.5 to 15% of surface-active
agents, from 0.1 to 10% of thixotropic agents, from 0 to 10% of suitable
additives, such as antifoams, corrosion inhibitors, stabilizers,
penetrating agents and adhesives and, as carrier, water or an organic
liquid in which the active substance is poorly soluble or insoluble:
certain organic solid substances or inorganic salts can be dissolved in
the carrier to help prevent settling or as antifreezes for the water.
By way of example, here is a flowable composition:
EXAMPLE F 10
______________________________________
compound 500 g
polycondensate of ethylene oxide with
50 g
tristyrylphenol phosphate
alkylphenol/ethylene oxide polycondensate
50 g
sodium polycarboxylate 20 g
ethylene glycol 50 g
organopolysiloxane oil (antifoam)
1 g
polysaccharide 0.5 g
water 316.5 g
______________________________________
Aqueous dispersions and emulsions, for example the compositions obtained by
diluting a wettable powder or an emulsifiable concentrate according to the
invention with water, are included within the general scope of the present
invention. The emulsions may be of the water-in-oil or oil-in-water type
and may have a thick consistency like that of a mayonnaise.
As for compositions which are adapted to storage and to transport, these
more advantageously contain from 0.5 to 95% (by weight) of active
substance.
The present invention also relates to a weeding method (especially of
monocotyledon crop areas (wheat, corn, rice)), which consists in applying
an effective quantity of a compound of formula (I) to the plants which are
to be destroyed.
During the application to a cultivated area, the application dosage should
be sufficient to control the generation of adventitious plants without
occasioning permanent substantial damage to the said crops. In this
context, then, an effective dosage means the dosage which enables this
result to be obtained.
The products and compositions according to the invention are preferably
applied to areas or terrains where it is desired to prevent the growth or
the development of plants which have not yet grown (preemergence
application). Nevertheless it will also be possible to employ a weeding
method which consists in applying an effective quantity of a compound of
formula (I) to the weeds to be removed when the latter have a green
foliage, advantageously the monocotyledons.
It is possible to operate so that the crop is sown before or after the
treatment.
The application dosage of active substance is generally between 1 and 8,000
g/ha.
The following examples illustrate the invention:
EXAMPLE A
Herbicidal Application During Preemergence of Plant Species
A number of seeds, determined depending on the plant species and the seed
size, are sown in 7.times.7.times.8 cm pots filled with light agricultural
soil.
The pots are treated by spraying with a spraying mixture in a quantity
corresponding to a volume application rate of 500 l/ha and containing the
active ingredient at the desired concentration.
The treatment with the spraying mixture is therefore applied to seeds which
are not covered with earth (the term spraying mixture is employed to
denote generally water-diluted compositions, as applied to the plants).
The spraying mixture employed for the treatment is a solution or suspension
of the active ingredient in a water/acetone mixture in proportions of
50/50, in the presence of 0.05% by weight of Cemulsol NP 10
(surface-active agent, consisting of a polycondensate of ethylene oxide
and alkylphenol, especially of a polycondensate of ethylene oxide and
nonylphenol) and 0.04% by weight of Tween 20 (surface-active agent
consisting of an oleate of a polycondensate of ethylene oxide derived from
sorbitol).
In the case of a suspension, the latter is obtained by mixing and milling
the ingredients in a micronizer so as to obtain a mean particle size of
less than 40 microns.
After treatment, the seeds are covered with a layer of earth approximately
3 mm in depth.
The pots are then placed in troughs intended to receive the moistening
water by subirrigation, and are maintained for 24 days at room temperature
under 70% relative humidity.
Scoring of the Herbicidal Activity
The recording is carried out as follows: at the end of 24 days, a
percentage (D) of destruction of the number of shoots in the treated pots
is measured in relation to the number of plants in the untreated (control)
pots. The remaining treated plants are used to measure the percentage of
reduction in size (RS) relative to the control plants.
The percentage of foliage volume not destroyed by the product is therefore
given by the formula:
##EQU1##
This value A is converted into a score from 0 to 5 according to the
following scale:
______________________________________
Score
______________________________________
0 to 10 5 (complete destruction)
10 to 30 4
30 to 50 3
50 to 70 2
70 to 90 1
90 to 100 0 (no effect)
______________________________________
The results obtained are shown after Example B for application rates of
4,000 g/ha.
EXAMPLE B
Herbicidal Application During Postemergence of Plant Species
A number of seeds, determined depending on the plant species and the seed
size, are sown in 7.times.7.times.8 cm pots filled with light agricultural
soil.
The seeds are then covered with a layer of soil approximately 3 mm in depth
and the seed is left to germinate until it gives rise to a plantlet at the
appropriate stage. The treatment stage for graminaceous plants is the
"second leaf being formed" stage. The treatment stage for dicotyledon
plants is the "cotyledons open, first true leaf being developed" stage.
The pots are then treated by spraying with a spraying mixture in a quantity
corresponding to a volume application rate of 500 l/ha and containing the
active ingredient at the desired concentration.
The spraying mixture has been prepared in the same way as in Example A.
The treated pots are next placed in troughs intended to receive the
moistening water by subirrigation, and are maintained for 24 days at room
temperature under 70% relative humidity.
Scoring of the Herbicidal Activity
The recording is carried out as follows: at the end of 24 days, a
percentage (D) of destruction of the number of shoots in the treated pot
is measured in relation to the number of plants in the untreated (control)
pots. The remaining treated plants are used to measure the percentage of
reduction in size (RS) relative to the control plants.
The percentage of foliage volume not destroyed by the product is therefore
given by the formula:
##EQU2##
This value A is converted into a score from 0 to 5 according to the
following scale:
______________________________________
Score
______________________________________
0 to 10 5 (complete destruction)
10 to 30 4
30 to 50 3
50 to 70 2
70 to 90 1
90 to 100 0 (no effect)
______________________________________
The results obtained are shown after Table A for application rates of 4,000
g/ha
The plant species employed in these Examples A and B are:
______________________________________
ENGLISH
ABBREVIATIONS
LATIN NAME NAME
______________________________________
AVE Avena fatua Wild oat
ALO Alopercurus myosuroides
Slender foxtail
ECH Echinochloa crusgalli
Panic grass
CYP Cyperus esculentus
Chufa flat sedge
DIG Digitaria sanguinalis
Hairy fingergrass
______________________________________
HERBICIDAL ACTIVITY AT PREEMERGENCE
COMPOUNDS NO.
AVE ECH DIG CYP ALO
______________________________________
1 5 5 5 3 --
2 1 4 4 0 --
4 5 5 5 3 5
8 2 4 5 1 2
9 5 5 5 3 4
11 1 5 5 3 5
12 5 5 5 3 5
13 5 5 5 2 5
14 4 5 5 4 5
15 5 5 5 3 5
16 3 5 5 3 5
17 3 5 5 3 5
23 0 5 5 1 5
24 5 5 5 2 5
25 5 5 5 3 5
______________________________________
HERBICIDAL ACTIVITY AT POSTEMERGENCE
COMPOUNDS NO.
ECH DIG ALO
______________________________________
11 0 3 3
13 4 3 2
15 5 3 3
16 3 0 3
17 3 0 3
24 3 1 3
______________________________________
EXAMPLE C
Test for Selectivity in Major Crops with Herbicidal Application During
Preemergence of the Plant Species
A number of seeds, determined depending on the plant species and the seed
size, are sown in 7.times.7.times.8 cm pots filled with light agricultural
soil.
The seeds are then covered with a layer of soil approximately 3 mm in
depth.
The pots are then treated by spraying with a spraying mixture in a quantity
corresponding to a volume application rate of 500 l/ha and containing the
active ingredient at the desired concentration.
The spraying mixture has been prepared in the same way as in Example A.
The treated pots are then placed in troughs intended to receive the
moistening water by subirrigation and are maintained for 24 days at room
temperature under 70% relative humidity.
Scoring of the Herbicidal Activity
The recording is carried out as follows: at the end of 24 days, a
percentage (D) of destruction of the number of shoots in the treated pot
is measured in relation to he number of plants in the untreated (control)
pots. The remaining treated plants are used to measure the percentage of
reduction in size (RS) relative to the control plants.
The percentage of foliage volume not destroyed by the product is therefore
given by the formula:
##EQU3##
This value A is converted into a score from 0 to 5 according to the
following scale:
______________________________________
Score
______________________________________
0 to 10 5 (complete destruction)
10 to 30 4
30 to 50 3
50 to 70 2
70 to 90 1
90 to 100 0 (no effect)
______________________________________
Thus, a product is judged to be selective in respect of the crop when the
scored value A is 0 or 1.
The results obtained are shown in Example C for application rates of 1 or 2
or 4 kg of active ingredient per hectare, depending on the products.
The plant species employed in this example are:
(1) In the case of the adventitious plants
______________________________________
ENGLISH
ABBREVIATIONS
LATIN NAME NAME
______________________________________
ECH Echinochloa crus-galli
Panic grass
DIG Digitaria snaguinalis
Hairy fingergrass
SOR Sorghum halepense
Johnson grass
SET Setaria faberii Giant foxtail
______________________________________
(2) In the case of the crops
__________________________________________________________________________
ABBREVIATIONS
LATIN NAME
ENGLISH NAME
__________________________________________________________________________
TRZ Triticum aestivum
Spring wheat
ZEA Zea mays Maize
ORY Oryza sativa
Rice
GLX Glycine maximum
Soybean
__________________________________________________________________________
TEST FOR SELECTIVITY IN
DOSE MAJOR CROPS HERBICIDAL
COMPOUNDS
APPLIED
ACTIVITY AT PREEMERGENCE
NO. (kg/ha)
ECH
DIG
SOR
SET
TRZ
ZEA
ORY
GLY
__________________________________________________________________________
1 2 3 5 5 2 0 0 0 1
4 2 5 5 1 5 0 0 1 0
9 2 5 5 2 2 0 0 3 0
13 2 4 5 2 4 0 1 2 0
14 2 3 5 3 4 0 2 0 0
15 2 5 5 5 5 1 0 3 0
__________________________________________________________________________
As can be seen from the table of results of this Example C, many products
exhibit an excellent antigraminaceous activity at preemergence while
showing an excellent selectivity for 1 or 2 or 3 or 4 of the 4 tested
crops=wheat, maize, rice, soybean.
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